crash in ata_completed with atapicam cd

[Sean McNeil]

I'm trying to track down my crash when I try to write a CD, but I'm not
familiar with amd64 assembly.  It is obviously an attempt to indirectly
jump to a routine:

ata_completed+0xcc:
	call	*%eax

where eax is 0xffffffff801a0fa8

Looking at ata-queue.c and an objdump of ata-queue.o, I see the call but
cannot tell where it corresponds to the C code.  It looks like there is
a return immediately following the indirect call, but I cannot see how
it aligns with the source.  Returns follow calls to ata_queue_request()
and ata_start().  Neither of which I should think would be indirect
calls.  The only place that looks right is at the end of the function
where it calls request->callback().

Can someone give me a hand in trying to interpret the assembly?

TIA,
Sean